1209469-24-8

Upstream product

• 188290-36-0 thiophene 
• 7766-50-9 1-undecen-11-ylbromide 

Downstream Products

• 1258753-88-6 C₅₈H₆₂O₈S₂ 

Relevant academic research and scientific papers

Fine tuning of solid-state properties of septithiophenes by tailoring the substituents

A series of five α, ω-substituted septithiophenes, which differ in the geometry of the peripheral branched alkyl substitutents, is presented. The position of the branching point has a substantial effect on the solubility and melting points of the oligomers. In contrast,. organic field-effect transistors (OFETs) that have been prepared from those materials via vapor deposition show all mobilities in the same range (0.18-0.018 cm 2V-1 s-1). The relative unsusceptibility of the mobilities on the molecular structure is attributed to the fact that all septithiophenes form smectic-like structures at room temperature under solid-state conditions, as revealed by temperature-dependent X-ray diffraction. Furthermore, four of the five oligomers exhibit thermotropic liquid crystalline smectic C phases. Strong interactions between the thiophene cores are assumed as driving forces for those structural features. Thus, tailoring the peripheral substituents makes it possible to fine-tune the thermal and solubility properties and, to a certain extent, the ordering under solid-state conditions. The ordering and the electrical properties are mainly dominated by the length of the core of the oligothiophenes.

Effect of Double Branching in α,ω-Substituted Oligothiophenes on Thermal Solid-State Properties

A systematic series of septi-, noni- and undecithiophenes and the corresponding pre-oligomers with five different dendrimer-like branched end-groups have been synthesized and their thermal solid-state properties investigated. The substituents vary in terms of the lengths of the linkers between the silicon branching points. Comparison of the compounds in the series reveals that the linker connecting the oligomeric core with the first branching point has the strongest effect on the thermal properties. Furthermore, the relatively large volume of the substituents causes surprisingly low overall transition enthalpies and entropies for the oligomers of 10–20 kJ mol–1 and 15–40 J mol–1 K–1, respectively, whereas the pre-oligomers with interrupted conjugation display values in the range of 15–40 kJ mol–1 and 40–100 J mol–1 K–1, respectively. Polarizing optical microscopy (POM) revealed textures pointing to smectic and columnar liquid-crystalline phases but X-ray and AFM data of a representative example are typical of cubic phases.

Predictability of thermal and electrical properties of end-capped oligothiophenes by a simple bulkiness parameter

The branching topology of end groups attached to several series of oligothiophenes has a systematic effect on thermal and electrical properties of the oligomers. The series were synthesized in a modular approach and show a distinct drop of the melting point Tm on increasing bulkiness of the substituents. The same trend can be found for the dissociation temperatures Tdis of aggregates in solution. Similarly, monolayer OFET mobilities μFET are significantly decreasing with increasing bulkiness of the substituents. A simple geometric model is presented quantitatively correlating the transition temperatures and mobilities with the substituents' structure based on a bulkiness parameter P, which allows predicting Tm, T dis, and μFET of corresponding not yet synthesized oligomers with branched substituents. This model might be generally applicable for end-capped rod-like conjugated oligomers.

Bent-core mesogens with thiophene units

Bent-core mesogens with thiophene and 2,2′-bithiophene units at the periphery of the aromatic core were synthesized and investigated by polarizing microscopy, XRD and electrooptical methods. Resorcinol, 2,7-naphthalenediol and 3,4′-biphenyldiol were used as bent units, phenyl thiophene-2-carboxylates form the rod-like wings and n-alkyl chains as well as olefin- and silylated-terminated alkyl chains were attached as flexible end-groups. A broad variety of different mesophase structures, incorporating ferroelectric and antiferroelectric switching smectic as well as modulated smectic phases, was obtained. Compared with the corresponding benzoates, these thiophene derived compounds form nearly identical LC phase structures, but have significantly reduced transition temperatures, which make them advantageous for applications.